Method and apparatus for producing cold



Dec. 14, 1937. E, MAN

METHOD AND APPARATUS FOR PRODUCING GOLD Filed sept.' 12, 19:56 l

Patented Dee.14,193r y A2,101,953

UNITED sTATl-:s PATENT ori-*ica METHOD AND APPAgAI'fUS FOR PRODUCING Erik Qman, Stocksund, Sweden Application September 12, 1936, Serial No. 100,546

' In Sweden September 21, 1935 15 claim (ci. riz-95) In several cases where artificial refrigeration prevent rusting of the vconduits it may be suitable is used the cold consumption is very variable. A to use a slightly alkaline solution. typical example thereof is the refrigeration in By using such a water solution the ice frozen dairies in which the cold consumption is great out is obtained in the form of crystals and not as during a few hours of the day but small if. none an ice mirror on the cooling surfaces. 'I'his is during the remaining part of the day, A refrigl of great advantage for the utilization of the ice erating plant for this and similar purposes calas e store of cold, as such ice or snow crystals do oulated for the highest load will, thus, be very `not adhere rigidly to the coolingy surfaces es iee large and expensive. mirrors do but are easily separable therefrom' In order to take up peak loads of a refrigerating and are further iD'Slieh e finely divided State that plant it has been proposed to provide the plant they are easily transportable either as such or 1 with a cold accumulator which is charged durtogethenwith solution in the form ofa suspension ing periods of low load and discharged during thereinf periods of high load. Hitherto these cold ac- The Cold ferffreezirlg meybej' delivered by a cumulators consisted of a bulk of a liquid of low refrigerator 0f 9'/ refrigerating maehine 01' @01d freezing point, the @01d contents of which as a air, especially in wintertime, or cold gases. In 15 consequence of its low temperature were utilized Order t0 facilitate the Seperetinrl 0f the Crystals for the accumulation. These contents are. howfrom the Cooling Surfaces the freezing maybe Celever, relatively low, and, thus, 19mg@ bulks of nqried out under agitation, or the cooling surfaces uid are required for taking up relatively greet maybe subjected t0 esereping, brushing or simi- 2') peaks of load. This is the case eve, when the lar action. Generally, the circulation of the 20 liquid is cooled down to very low temperatures. solution through the freezing vessel is, however, XVhCh, hovjever requires, a corresponding W Sumcient fOr :the Separation 0f the crystals. The temperature of the refrigerant used which is uneeeiiiig Surface melf be submerged'into ,the S0111-v favourable from the point of view of refrlgeration 0r the Solution may be brought t0 Sprinkle tion. down on the surface. 'I'he cooling surface may 25 It has also been proposed for Cold storage to be movable, e. g. have the form of a drum. utilize the heat of melting which is given oi by The freezing may be extended more 0r 1eSS far, a substance when passing from the solid phase e- 8- until metete! quantity 0f Soil/eilt iS transinto the liquid phase. However, in such cases ferled 111150 Solid Phase- The mixture 0f iee 20 the substance was enclosed in a cooling element Crystals and solution may as such be used as store 30 in which on freezing it-forined a coherent solid of e01d,b11t usually itis preferred to separate the l body the cold contents of which Could only be solid phase, i. e. the ice crystals, frdm the solution, utilized within said cooling element proper, before cold is withdrawn. This separation may The present invention relates to a method for Preferably take Piace more 0r ieSS COHDUOUSIM 5 producing cold in refrigerating plants operating When the freezing is carried out in vessels, in 35 at varying loads which permits storage of Cold in which the cooling surface is submerged in the an eective and economical manner and utiliza.- solution, the ice crystals will rise to the surface tion of said cold at any desired place. The methand collent there in the form of ala-Ver which is od comprises subjecting a solution of a 'substance easily remeveblef i in a solvent (brine) to a temperature below the In nder to carry ont the freezing operation 40 freezing point of the solution by means ofiexcess -in a slution of as 10W concnntranon as possible cf cold at disposal at low or no load, thereby which is suitable from the pnlnt of new of Teme' causing solvent or solution to be transferred into eration' conntrated solution fnrmed'dnnng the solid phase in the form of crystals, and withdraw. freezing Operation may be removed from the ing cold at high load from the solid phase thus free-fing `vessel more er less continuously and obtained by said solid phase being transferred fresh Semtionbe substituted therefor more 0r less into liquid phase. continuously. As solvent one may use water and as substance Preferably. the COld lis Withdrawn flOm the dissolved therein a salt or salts, i. e. a soluble solid phase (ice or snow crystals) by means of a' 50 chloride, sulphate, carbonate, nitrate and the like, solution which may be pf the same kind as that especially of alkalinetals, either alone or two or used during the freezing operation, said solution more in admixture. Instead of salts it is, howbeing pumped through the store of cold .and-the ever, also possible to use alkalles, acids, alcohol, cold consuming place (cold'conslmier) and thence sugar, glycerin, glycol and so on. In order` to back to the store of cold. When the solution is 55 passing through the stor of cold or cold storer so 'much of the ice or snow crystals is melted as to cause the solution to be cooled down onto or nearly onto the freezing point, and when it is passing through the cold consumer the temperature rises, then falling again in the cold storer and so on.

In many cases it is suitable to carry out the freezing operation out of a solution having an eutectical point. In such cases the freezing Ais preferably carried out at the same temperature at which cold is withdrawn from the solid phase, and out of a solution which has its eutecticum at this temperature.

are:

Percent C. KCl-solution of 19.3 eutectic temperature 9 KNOs-solution of 11.2 eutectic temperature 3 ZnSOpsolution of 27.2 eutectic temperature 6.5"

Al2(SO4)5-solution of 23 eutectic temperature 4 with regard to concentration as well as to tem'- perature by adding substances, especially salts, whereby it is always possible to procure a solution having the desired eutectic point.

The invention will be more fully described with reference to embodiments of same showndia-A numeral I0 designates a vessel, the freezing vessel, connected over a oat valve II with a receptacle I2 arranged at a higher-level than the vessel I0 and serving as storage container for the brine to be'frozen. This brine flows by its own weight from the receptacle I2 into the freezing vessel I0 in which it is held at constant level v by the oat valve I I. The vessel I0 is provided f' with means for cooling the brine contained therein, said means, according to the gure, comprising a cooling coil I3, e. g. the refrigerator coil of a refrigeratirne,r machine. However, said means may also consist of any other cooling device, e. g. a cooling drum, cooling pan or the like. By any suitable means, e. g. an agitator scraping device or the like, the cooling surface in the' freezing vessel I0 maybe held clean. 'I'he ice (snow) formed collects on the surface of the brine in the freezing vessel I0, from where it is conveyed byl means of any suitable means, e. g. the conveyor I4, into a container I5 arranged at a higher level than the vessel I0 and also receptacle I2, said container I5 serving as storer or accumulator for the ice produced. The conveyor I4 is so arranged as to permit solution carried along by the ice to flow back into the freezing vessel III. The storer I5 is provided with a perforated bottom I6, and the space below said bottom is connected with the upper part of the freezing vessel I0 by means of a conduit I1. The storer I5 is also connected with receptacle I2 by means of a conduit 20 which, preferably, opens at the bottom of said receptacle. Y

According as ice is formed in the freezing vessel I0 the concentration of the brine in said vessel would rise continuously. However, such an increase of concentration would cause a corresponding fall of the freezing point of the brine would have to deliver cold through the cooling coil I3 of a corresponding lower temperature.

Examples of such solutions The eutectic point of 'a solution may be variedI InV order to preven.l an increase of concentration in the freezing vessel I0, one may remove concentrated solution which has collected at the bottom of said vessel through a conduit 2| e. g. by means of a pump '22'whch conducts said s'olution through a conduit 23 into a container 24. After corresponding dilution in a diluting receptacle 26 the solution may be returned to the receptacle I2.

In this manner it is possible to continue the freezi of the brine in the freezing vesselv III withou `'the concentration ,in said vessel rising too much.` The liquid level in receptacle I2 sinks, and more and more s now is accumulated in storer I5 which is hereby charged.

30 designates a cold consumer operating at varying load and connected with the cold storer I5k through an inlet conduit 3| and an outlet conduit 32, the latte'rconduit having a pump 33 inserted therein.` The cold is preferably withdrawn by means of a solution, which is circulated by the pump 33 from the cold storer I5 through conduit 3|, cold consumer 30 and conduit 32 back to the cold storer I5. Preferably, this solution is of the same kind as that of the freezingl system III, I2, I5 and should, preferably, be concentrated. As such solution one may to advantagel y use concentrated solution from the container 24, a pump 35 Aconducting saidsolution to the cold storer I5 through a conduit 36. It is suitableV to have the solution in the cold storer I5 to circulate from below and upwards as hereby ice crystals will be brought along by the solution, thereby increasing the cooling capacity thereof. However, the direction 4of circulation may also be'reversed, in which case solution from the conduit 3l v'is caused to sprinkle down over the ice in the storer I5 which needs not to be filled with solution which is necessary in the former case.` The solution or the mixture of solution and ice crystals enters the cold consumer at lo-w temperature, is heated therein and returns at a somewhat higher temperature to the cold storer I5 in which it melts some ice and is again cooled down and so on. The circulation is continued, until a sucient quantity of cold has been withdrawn from the storer or until the total quantity of ie therein has been melted (=discharged storer).

Duringthis discharge the freezing system I0, I2, `I5 may be ut out. When the cold storeris to be re-charged the solution of the storer I5 which is now diluted is conducted therefrom through j conduit 2 0 into storage receptacle I2 by self-flow or by the pump 22. The solution in the discharge system 30, 3|, 32 may preferably be retained. Thereafter the period of discharge begins again.

In the-embodiment according to Fig. 1 the storage receptacle I2 and the cold storer I5 are placed at such a level in relation to each other and to the freezing vessel I0 as to permit the brine to flow by its own weight from the cold storer to freezing vessel and storage receptacle and from the latter to freezing vessel, whereas the ice produced is conveyed from freezing vessel I0 to cold ,storer I5 by means of a conveying dev ice. In the embodiment shown in Fig.. 2 thev cold storer I5 is placed at a lower level than freezing vessel I Il and storage receptacle I2, the solution being pumped from the cold storer I5 to the two other receptacles,-whereas the ice produced is conveyed from lthe freezing vessel II) to the cold storer I5 along an inclined surface III Without any 'mechanical conveying means. From the cold storer I5 solution is pumped through conduit 4I byl a pump 42 into the upper part ofthe freezing vessel I0, and at the end of the period of discharge the diluted solution is pumped through conduit 43 and pump 114 back to the storage receptacle I2, into which. it 'is introduced at the bot"- tom. -As in the previous embodiment the same pump 44 may also serve to remove concentrated solution from freezing vessel I0 through conduit 2|. Concentrated solution is introduced at the bottom of the storage receptaclek I2, it being suitable during the charging period to retain the concentrated solution in said receptacle as a layer on the bottom of same. For this purpose the outlet from the storage receptacle I2 to the float valve II is arranged at a distance from the bottom. Preferably, two or more such outlets 45 are provided at diierent levels. In'this manner it is possible to feed the freezing vessel I0 with diluted l centrated solution from the freezing vessel I0 are used as circulating solution in the vdischarge system 30 to 33 in the manner above described.

In Fig. 3 an embodiment is shown diagrammatically in which freezing vessel, storagel receptacle for brine and cold storer areV built to-f gether to one unit'. The freezing 'system consists of a single vess i 50 filled with brine in which the cooling coil I3, ubmerged. Provided within the vessel 50 is a` partition 5I separating. achamber 52 serving as freezing space. from a chamber 53 serving, as combined brine storage receptacle and cold storer. The discharge system 30 to 33 is connected with chamber 53a mixture of solution and ice crystals collected on the surface being circulated through said system.

. The embodiment shown in Fig. 3 may be further simplified by removing the partition 5I, in which case, consequently, during thecharging period the ice is 4permitted to remain in the freezing vessel, which; thus, also serves as cold storer. An example of such an arrangement is shown in Fig. 4.

In this figure, 55 designates a combined freezing vessel and cold` storer filled with brine in which the cooling coil I 3 from e. g. a refrigerating machine is submerged as before. Pfeferably, an.

agitator 56 bis provided in the vessel 55. ADuring the charging period, i. e. at low load of the cold consumer 3ll,v ice is formed in the vessel 55, and

during the discharging period solution or a mixture of ice crystals and solution is brought to circulate through the cold consumer 30, e. g; by means o f pump 33.

Evidently, two or more such apparatuses which serve both as freezing vessel and cold storer may in dii'erent manner be combined with one or more cold consumers. The arrangement may be such that one (or more) of the apparatuses is permanently connected with the circulation system of the cold consumer, whereas anotherapparatus (or other apparatuses) may be connected with-or disconnected from said system in such manner as to be cut out at low load of the cold consumer whilev being charged with ice, and to be automatically switched in at increasing load, when the temperature has attained a given value,

thereby serving as cold storer. The apparatuses may operate with solution of the same or diiferent concentration. In certain cases the temperature of the apparatus permanently switched in may be so high that no ice is formed in same. The apparatus in which ice is formed should be provided with an agitator, scraper, brush or the like to remove the ice crystals from the cooling surfaces, which means may be in function, only when ice ,is frozen out in the apparatus, i. e. during the charging period. 'This may for instance be effected by a driving means for said ice removing means being controlled by the temperature of the solution in the apparatus in such manner that the driving means is automatically started, when said temperature has sunk to the freezing point of the solution (formation of ice), and is automatically cutout, when the temperature has risen beyond this value.

As mentioned above it is suitable in certain cases to operate with a solution with eutecticum.'

In such case the freezing may take place at the eutectic point of the solution so as to cause a mix- `ture of ice crystals and salt crystals to be formed. Also theA withdrawal of cold by means of a solution, preferably of Ithe same concentration and composition as that out of which the freezing has taken place is eifected at the eutectic temperature of theI solution. By suitably selecting the dissolved substance i this temperature may be 'varied at..will. Especially in the embodiments shown in Figs. 3 and 4 it is suitable to operate with solutions with eutecticum. What I claim iszl g l. A method of producing cold in refrigerating yplants which operate at varying load, comprising subjecting a solution of a substance in a solvent to a temperature below its freezing point by means of excess of cold at disposal at low load'y thereby causing solvent to be transferred into solid phase in the form of crystals, separating solid phase from the solutionftransferring` at high load such separated solid phase into liquid phase, and utilizing the cold thus produced.

2. A method of producing cold in refrigerati-ng plants which operate at varyingload, comprising subjecting a solution of a substance in a solvent 'to va temperature below its freezing point by means of excess of cold at `disposal at low load, thereby causing .solvent to be transferred into solid phase in the form of crystals, continuously separating solid phase from the solution, transferring at high load such separated solid phase into liquid phase, and utilizing the cold thusproduced.

. 3. A method of producing cold in refrigerating plants which operate at varying load, comprising subjecting a solution rof a substance in a solvent to a temperature below itsfreezing point by means of excess of cold at disposal at low load, thereby causing solvent to be transferred into solid phase in the form of crystals, continuously separating solid phase from the Surface of theof a substance ina solvent, and utilizing the cold thus produced.

5. A method of producing cold in refrigerating plants which operate at varying load, comprising subjecting a solution of a substance in a solvent to a temperature below its freezing point by means of excess of cold at disposal at low load, thereby causing solvent to be transferred into solid phase in the form of crystals, separating solid phase from the solution, transferring at high load such separated solid phase into liquid phase by bringing it into contact with a solution of the same substance in the same solvent as those of the solution which was subjected to freezing, and utilizing the cold thus produced.

6. A method of producing cold in refrigerating plants which operate at varying load, comprising subjecting a solution of a substance in a solvent to a temperature below its freezing point by means of excess of cold at disposal at low load, thereby causing solvent to be transferred into solid phase' in the form of crystals, removing concentrated solution formed during freezing and replacing same by fresh solution, transferring at high load solid phase thus obtained into liquid phase, and utilizing the cold thus produced.

.7. A method of producing cold in refrigerating plants which operate at'varying load, comprising subjecting a solution of a substance in a solvent to a temperature below its freezing point by means of excess of cold at disposal at low load, f

replacing same bysfresh solution, separating solid.

phasel from the solution, transferring at high load s'uch separated solid phase into liquid phase, and utilizing the cold -thus produced.

8. A method of producing cold in refrigerating plants which operate at varying load, comprising subjecting va solution of a substance in a solvent to a Itemperature below its freezing point by means of excess of cold at disposal at low load, thereby causing solvent to be transferred into solid phase in the form of crystals, continuously removing concentrated solution formed during freezing and continuously replacing same by fresh solution, separating solid phase from the solution, transferring at high load such separated solid phase into liquid phase, and utilizing the cold thus produced.

9. A method of producing cold inrefrigerating plants which operate aty varying load, comprising subjecting a solution of a substance in a solvent to a temperature below its freezing point by means of excess of cold at disposal atlow load, thereby causing solvent to be transferred -into solid phase in the form of crystals, removing concentrated solution formed during freezing and replacing same by fresh solution, separating solid phase from the solution, transferring at high load such separated solid phase into liquid phase by bringing it into contact with concentrated solution thus removed, and utilizing the cold thus produced.

10. A method of producing cold in'refrigerating plants lwhich operate at varying load, comprising subjecting an eutectic solution of a substance in a solvent to its eutectic temperature by A means of excess of cold at disposal at low load, thereby causing solution to be transferred into solid phase in the form of crystals, separating solid phase from the solution, transferring such separated solid phase into liquid phase at said eutectic temperature, and utilizing the cold thus produced.

11. An apparatus for producing cold to be used by a cold consumer operating at` varying load,

. comprising a vessel, a receptacle for a solution of a substance in a solvent, means to feed said vessel with solution from said receptacle, means to supply cold to said vessel soas lto freeze outcrystals from the solution contained therein, a. storer, means to feed said storer with crystals from the freezing vessel, and means to connect said storer in closed circuit with saidv cold consumer.

12. An apparatus for producing cold to be used by a cold consumer operating at varying load, comprising a vessel, a receptacle for a solution of a substance in a solvent. means to feed said vessel with solution from said receptacle, means to supply cold to said vessel so as to freeze out crystals from the solution contained therein, a storer, means to feed said storer with crystals from the freezing vessel, and means comprising a pump izo-connect said storer in closed circuit with said cold consumer.

13. An apparatus for producing cold to be used by a, cold consumer operating at varying load, comprising a vessel, a receptacle for a solution of a substance in a solvent, means to feed said vvessel with solution from said receptacle, means to supply cold to said vessel so as to freeze out crystals from the solution contained therein, means to remove from the freezing vessel concentrated solution formed during the freezing, a storer, means to feed said storer with crystals from said freezing vessel, and means to connect said storer in closed circuit with said cold consumer.

14. An apparatus for producing. cold to be used by a cold consumer operating at varying load, comprising a vessel, a receptacle for a solution of a substance in a solvent, means continuously to feed said vessel with solution from said receptacle, means to supply cold 'to said vessel so as to freeze out crystals from the solution contained therein, a storer, means continuously to feed said storer with 'crystals from the freezing vessel, and' means to connect said storer in closed circuit with said cold consumer.

15. An apparatus for producing cold to be used by a cold consumer operating at varying\load, comprising a vessel, a receptacle for a solution of al substance in a solvent, means to feed said vessel with solution from said receptacle, means .Ito supply cold to said vessel so as to freeze out ERIK MAN. 

